Excavator door mounting



YEW 27, 1948- w. s. BURDICK 2,434,902

EXCAVA'IKOR DOOR MOUNTING Filed Aug. 27, 1945 2 Sheets-Sheet 1 Arm/(WE X Jan. 27, 1948' w. s. BURDICK A 2,434,902

EXCAVATOR DOOR MOUNTING File 27, 9 2 Sheets-Sheet 2 INVENTOR. W471 fl Patented Jan. 27, 1948 EXCAVATOR DOOR MOUNTING Will S. Burdick, Wauwatosa, Wis., assignor to Harnischfeger Corporation, Milwaukee, Wis., a corporation of Wisconsin Application August 27, 1945, Serial No. 612,893 2 Claims. (01. 214146) The invention relates to excavating shovels and more particularly to the dippers thereof.

Dippers for excavating shovels have a swinging door covering the bottom of the dipper and locked in closed position by a latch controlled by the operator. On the release of the latch the door swings open due to its weight and that of the material in the dipper to discharge the load. For closing the door, the dipper stick is swung by the operator with a pendulum-like motion, so that the door will be swung into latched engagement with the dipper body. With a free swinging door it sometimes happens that the door is swung or slammed so hard against the dipper in closing as to break portion-s of the door structure. The object of the present invention is to provide an automatic control over the swinging action of the door to resist too rapid slamming of the door against the dipper by the operator by introducing a frictional restraint against the free swinging of the door, this restraint being variable depending upon how far the door is from its closed position, the greater the door opening the more restraint to the closing of the door.

A further object of the invention is to provide a frictionally imposed restraint to the free swinging of the dipper door in which the restraining means is distinct from the door pivot and is preferably associated with a toggle linkage between the door and the dipper stick.

The invention further consists in the several features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a side elevation view of a shovel dipper equipped with a control embodying the invention;

Fig. 2 is a bottom plan view of the dipper;

Fig. 3 is a. detailed vertical sectional View taken on the broken line 33 of Fig. 1;

Fig. 4 is a, detailed sectional view taken along the line 4l of Fig. 3.

Referring to the drawings, the numeral 4 designates a shovel dipper of any suitable construction having the hoist bail 5, the dipper stick pin mountings 6 pivotally connecting it with the dipper stick I, the brace links 8 operatively connecting its back with said stick, the door hinges 9 carrying the hinge pins Ill for the swinging door I! provided with the usual spring pressed latch l2 to engage the keeper IS on the front of the dipper. As shown in Fig. 2, the latch i2 is controlled by the operator through a release lever l4 and a pull cord or cable [5. All of the above parts are of conventional construction.

In operating dippers of the type above described, the operator through his movement of the dipper stick I imparts a swinging movement to the door relative to the dipper and in this way moves the door to a closed position where it is held by the latch. Sometimes the door is slammed or swung so violently against the dipper that it is fractured, and to avoid this means are herein provided for checking or restraining the free swinging movement of the door.

As herein shown, this restraining means comprises a pair of frictional devices which are mounted in the knee joints of a pair of toggle levers l6 and H, the lever l6 being pivotally connected at I8 to the door at a point removed from its pivot and the lever I! being pivotally connected at l9 to a transversely disposed shaft 20 mounted on the dipper stick I.

Each frictional device, as shown in Fig. 4, includes a friction disk 2| interposed between adjoining pivoted ends of the levers l6 and I1 and held in frictional engagement therewith by means of a bolt 22 secured to one of the levers and passing through both levers, said disk and a wear plate 23 disposed on the outer side of the other lever. A spring 24 is mounted on the exposed end of the bolt 22 between the plate 25 and a washer 26 and tensioning nut 21, said spring exerting pressure on said plate 23, the levers IE3 and H and the disk 2! tending to resist a swing of said levers l6 and H relative to each other which occurs when the dipper door H is swung from its dotted line open position to its closed position shown in Fig. 1, and since the levers are moved through a greater angle the farther the door is swung to open position a greater frictional force is present to retard the closing of the door the farther that it is opened. Such a frictional restraint prevents the door from being swung by the operator so violently as to cause the door breakage liable to occur with a freely swinging door. It will be noted that with the use of the frictional devices on the knees of the toggle levers that the leverage of the damping force changes as the amplitude of the swing changes and increases with an increase in swing of the door.

I desire it to be understood that this invention is not to be limited to any particular form or arrangement of parts except insofar as such limitations are included in the claims.

What I claim as my invention is:

1. In an excavating machine having a dipper stick, the combination of a dipper mounted on said stick and having a door mounted to swing relative to said clipper, and friction producing devices connected with said door and the dipper 3 stick and acting to restrain free swinging of said door.

2. In an excavating machine having a dipper stick, the combination of a dipper mounted on said stick and having a door mounted to swing relative to said dipper, a pair of toggle levers connecting said door with said dipper stick, and means for producing frictional resistance at the knee joint of said levers to restrain free swinging Number of said door.

WILL S. BURDICK.

REFERENCES CITED The following references are of record in vthe file of this patent:

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